BACKGROUND AND PURPOSE: The beneficial effect of intravenous thrombolytic therapy in patients with acute ischemic stroke attributable to internal carotid artery (ICA) occlusion remains unclear. The aim of this study was to evaluate the efficacy and safety of intravenous recombinant tissue-type plasminogen activator in these patients.MethodsICARO was a case-control multicenter study on prospectively collected data. Patients with acute ischemic stroke and ICA occlusion treated with intravenous recombinant tissue-type plasminogen activator within 4.5 hours from symptom onset (cases) were compared to matched patients with acute stroke and ICA occlusion not treated with recombinant tissue-type plasminogen activator (controls). Cases and controls were matched for age, gender, and stroke severity. The efficacy outcome was disability at 90 days assessed by the modified Rankin Scale, dichotomized as favorable (score of 0-2) or unfavorable (score of 3-6). Safety outcomes were death and any intracranial bleeding.ResultsIncluded in the analysis were 253 cases and 253 controls. Seventy-three cases (28.9%) had a favorable outcome as compared with 52 controls (20.6%; adjusted odds ratio (OR), 1.80; 95% confidence interval [CI], 1.03-3.15; P=0.037). A total of 104 patients died, 65 cases (25.7%) and 39 controls (15.4%; adjusted OR, 2.28; 95% CI, 1.36-3.22; P=0.001). There were more fatal bleedings (2.8% versus 0.4%; OR, 7.17; 95% CI, 0.87-58.71; P=0.068) in the cases than in the controls.ConclusionsIn patients with stroke attributable to ICA occlusion, thrombolytic therapy results in a significant reduction in the proportion of patients dependent in activities of daily living. Increases in death and any intracranial bleeding were the trade-offs for this clinical benefit.